Global and domestic demand for fossil fuels continues to rise despite price increases and other economic and geopolitical concerns. As such demand continues to rise, research and investigation into finding additional economically viable sources of fossil fuels correspondingly increases. Historically, many have recognized the vast quantities of energy stored in oil shale, coal and tar sand deposits, for example. However, these sources remain a difficult challenge in terms of economically competitive recovery. Oil shale and tar sands in particular represent a tremendous volume of raw materials and remain a substantially underutilized resource. A large number of companies and investigators continue to study and test methods of recovering oil from such reserves. In the oil shale industry, for example, methods of extraction have included in-situ methods such as In-Situ Conversion Process (ICP) method (Shell Oil), combustion within steel fabricated retorts, and more recently constructed in-capsule methods such as the In-Capsule® Technology (Red Leaf Resources).
Among the various processes for extracting hydrocarbons from oil shale and tar sands, all face challenges in economics and environmental concerns. For example, some processes require a large energy input or consume a large volume of water. Other processes can create a risk of surface or ground water contamination or air pollution. Moreover, global warming concerns give rise to additional measures to address carbon dioxide (CO2) emissions which are associated with such processes. An effective process should accomplish environmental stewardship, yet still provide high volume energy fuel output.
Large scale stationary constructed impoundments have recently been developed with the goal of addressing both the economic and environmental concerns inherent in extracting hydrocarbons from hydrocarbonaceous materials. These methods are currently known as EcoShale® In-Capsule® Technology and include forming a body of comminuted hydrocarbonaceous material encapsulated inside a fluid barrier. The hydrocarbonaceous material is usually rubbilized to allow for better combustion and heating permeability. Permeability is generally desired because pyrolysis, the method by which the hydrocarbons are extracted, can be achieved under high permeability conditions with greater quality and production with lower energy input. The fluid barrier can prevent the escape of liquids and vapors from the encapsulated volume, as well as avoid ingress of gases and liquids from outside sources. The hydrocarbonaceous material is heated inside the encapsulated volume, triggering pyrolysis to form flowable hydrocarbons and allowing their extraction.
Often in such processes, the fluid barrier is constructed from earthen materials such as clay, compacted fill, sand, or gravel. Large volumes can be encapsulated by using inexpensive earthen materials. In some arrangements the fluid barrier has multiple layers of materials that are chosen for their ability to restrict the movement of fluids into and out of the encapsulated volume. For example, in some processes the walls of the encapsulated volume are berms of compacted fill, with a layer of hydrated bentonite amended soil on the inner surfaces. The hydrated bentonite amended soil is generally effective at restricting movement of liquids and gases across the fluid barrier as long as hydration is maintained.
The fluid barrier contributes to making these processes more economic and environmentally safe. The processes can be optimized by controlling pressure, temperature, and chemical composition inside the encapsulated volume. This allows for higher volume fuel production with less energy input and water consumption. The fluid barrier also protects the environment by preventing pollutants from escaping. This solves problems with air pollution and surface and ground water contamination. For such processes to be effective the fluid barrier retains produced hydrocarbons inside the encapsulated volume for extraction and so materials do not escape into the environment in an uncontrolled manner.